function s1_hello() {
  echo "hello, world!"
}

function s2_tell_who_i_am() {
 echo "$(whoami)"
}

function s3_which_distro_do_i_use() {
  if [ -f /etc/os-release ]; then
     . /etc/os-release
     echo "NAME=\"$NAME\""
  elif [ -f /etc/redhat-release ]; then
     DISTRO=$(cat /etc/redhat-release)
     echo "NAME=\"$(echo $DISTRO | awk '{print $l}')\""
  else
     echo "NAME=\"没有发现版本信息!\""
  fi
}

function s4_view_my_cpu_arch() {
  local cpu_arch=$(uname -m)

  case "$cpu_arch" in
        x86_64|amd64)
          echo "x86_64"
          ;;
         *)
            echo "未能识别CPU:$cpu_arch"
          ;;
  esac
}

function s5_show_main_memory_size_in_megabytes() {
   disk_size_gb=$(lsblk -bno SIZE /dev/sd? --exclude 1 | tail -n +2 | awk 'NR==1{print $1/1024/1024/1024}')

   echo -n "${disk_size_gb%.*}"
}

function s6_show_main_memory_size_in_megabytes() {
        free -m | grep "Mem:" |awk '{print $2}'
}

















